Not only does capital punishment not deter crime but it's more expensive than keeping a convicted murderer in prison for life.

Former Egyptian President Mohamed Mursi waves at his trial with other Muslim Brotherhood members in Cairo, in May. He was subsequently sentenced to death. Egypt is among a handful of African countries that regularly execute.
Reuters/Mohamed Abd El Ghany1 août 2015

Over recent weeks there has been a constant background noise that Islamic State and its ideology are some sort of throwback to a distant past. It is often framed in language used last week by the deputy…